The increasing demand for lower power consumption and environmentally friendly consumer devices has resulted in interest in power supply circuits with “green” technology. For example, on average, a notebook power adapter continuously “plugged in” spends 67% of its time in idle mode. Even with a power adapter which conforms to the regulatory requirement of dissipating less then 0.5 watts/hour, this extended idle time adds up to 3000 watt hours of wasted energy each year per adapter. When calculating the wasted energy of the numerous idle power adapters, the power lost is considerable.
Power strips are used to multiply the number of AC outlets available from a single AC socket. In an office or home environment, a computer, monitor, printer, scanner, and other electronic devices are often connected to the same power strip. When not in use, these connected devices will often be left on and go into self-imposed idle modes that typically consume less than 1 watt per device. Even though each is consuming standby power, the total power delivered by the power strip can be as much as the number of outlets used times the idle power, perhaps as great as 6 watts or more. This multiplicity of wasted idle power can be reduced or eliminated if the power strip can learn or be programmed to sense the idle condition of each outlet and turn that outlet off if idle conditions are present.